This invention relates to a micromechanical pressure sensor of the type known as the molecular drag gauge with an improved range, and more particularly to an improvement to the type of micromechanical pressure gauges disclosed in the U.S. Pat. No. 5,528,939 issued Jun. 25, 1996 and assigned to the Assignee of the present invention.
For the measurement of pressure in vacuum systems, it has been known to use a molecular drag gauge which makes use of the property that the drag force produced by a gas at a low pressure on an object moving therethrough is proportional to the pressure of the gas. Aforementioned U.S. Pat. No. 5,528,939, which is hereby incorporated by reference, disclosed micromechanical pressure gauges of this kind adapted to cause one or more members to vibrate electrostatically in the proximity of a stationary member and to measure the molecular drag force that operates to damp the vibrations.
It is desirable to have pressure gauges with an extended sensor range because, although typical vacuum systems utilize two or more types of gauges each having its own range of usefulness, switching between different gauges is not only troublesome but also inclined to introduce reading discontinuities.